1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to managing data, and more particularly, to managing data by dividing file identifier descriptors (FIDs) included in metadata of universal disk format (UDF) file system and arranging them.
2. Description of the Related Art
In general, an operating system (OS) uses a file system in order to manage data. The file system is an essential component having a logical structure for the management of data. For example, the format command in Microsoft Windows is a process of creating the file system and initializing it. That is, a user cannot store or delete files until a file system has been created.
Different OSs use different file systems. For example, file allocation table (FAT) and new technology file system (NTFS) are used in the Windows operating system, and the Unix file system (UFS), extended 2 (EXT2), extended 3 (EXT3), and journaling file system (JFS) are used in Unix, Linux and variants thereof. Each file system provides extra functions such as data coding and data compression.
The file system organizes and stores files, and is divided into a data area where real data (e.g., a file or a directory) is stored, and an information area where information on the data stored in the data area is stored. That is, the information on the property, access permission, access time, size, and location of the data is stored in the information area.
In contrast, the UDF is a file system standard for an optical medium, which was developed by OSTA. UDF is used in place of a conventional ISO 9660 file systems, which are not suitable for optical media such as digital versatile discs (DVDs) and compact disc rewritables (CD-RWs), and has functions to read the data of one file at a time without wasting overhead, and to partially or completely delete the file on the CD-RW medium using a new technique called packet writing.
A UDF system is divided into a data area where data is stored and a data entry area where information on the data stored in the data area is stored. Here, the data includes files and directories. The data area of the file stores a real file, whereas the data area of the directory stores information on the file and subdirectory.
The data area of the directory storing the information on the file and subdirectory is called a directory area and information on the file and subdirectory included in a corresponding directory is recorded in the form of an FID therein. The FID includes the name of the file or subdirectory and information on a save location thereof.
Metadata refers to a data entry area of the file in the case of the file, and the sum of the data entry area and the directory area in the case of the directory and FIG. 1 illustrates metadata 100 of a related art directory.
Referring to FIG. 1, the data entry areas 11, 13, and 15 of the directory and the directory areas 12, 14, and 16 are arranged. FIDs 111, 112, 113, 114, 121, 122, 123, 131, and 132 are respectively arranged in the directory areas 12, 14, and 16.
Here, when searching for a file “FILE—6” 131 along a path “DIR—1/DIR—2/FILE—6”, a device executes a search by referring to the metadata 100 in the order the FIDs included therein were created.
That is, the device respectively searches for “FILE—1” 111, “FILE—2” 112, and “DIR—1” 113 arranged in a directory area 12 of a root directory 110. Then, the device respectively searches for “FILE—4” 121, “FILE—5” 122, and “DIR—2” 123 arranged in a directory area 14 of a directory “DIR—1” 120.
Specifically, the device searches for the files “FILE—1” 111 and “FILE—2” 112 in order to search for the directory “DIR—1” 113 in the directory area 12 of the root directory 100, thereby wasting computer resources and increasing the search time. This is particularly disadvantageous for the UDF file system storing a large number of files and directories.
Therefore, a new method that can reduce the waste of computer resources and the search time in the UDF file system is needed.